A Saint andrews cross is an upright crucifix-type cross that is used mainly for bondage and corporal punishment.

The submissive would be restrained on the cross with their feet still on the ground and their arms restrained at the wrist along the two ends of the cross.

Submissives can be restrained on the cross facing either away from the dominant or towards the dominant, depending on the activity that is being undertaken. Play that would require facing away from the dominant would be spanking or other corporal punishment, and play that would require facing the dominant might be nipple torture, spitting or CBT/ball busting.

The idea of the cross is that the submissive is very exposed whilst restrained.